Polymeric materials such as acrylics, vinyl chloride homopolymers and copolymers, styrene-butadiene copolymers, vinylidene chloride copolymers, vinyl acetate copolymers and styrene-butadiene-acrylonitrile terpolymers have been utilized in the textile industry in the production of coated fabrics. These polymeric materials are generally employed as a backcoating for textile fabrics which are used in producing home furnishings and furniture upholstery, such as placemats, tablecloths, bed and mattress covers, and draperies.
U.S. Pat. No. 3,607,341, the disclosure of which is herein incorporated by reference, describes a process for producing coated textile fabrics by foaming an aqueous emulsion polymerized latex composition, applying the foam to the fabric, crushing the partially dried and uncured foam, and thereafter drying and curing the crushed foam. Typical latexes used in this coating process are those prepared by polymerizing at least two ethylenically unsaturated monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, acrolein, styrene, ethyl acrylate, butyl acrylate, acrylonitrile, vinyl chloride, vinylidene chloride and the like. The curing step of the latex is generally carried out using conventional crosslinking agents, along with other additives such as catalysts or accelerators. Typical catalysts used in the cure of latexes include organic acids such as citric acid, oxalic acid, and p-toluene sulfonic acid.
U.S. Pat. No. 2,931,749 discloses fabrics bonded by a water-insoluble emulsion copolymer containing acrylic acid, methacrylic acid, itaconic acid, and salts thereof, where the copolymer is crosslinked to an insoluble condition by exposure to heat.
U.S. Pat. No. 3,157,562 discloses a fabric coating composition comprising an aqueous dispersion of a N-methylolamide/(meth)acrylic acid polymer, (meth)acrylamide, and other monomers such as acrylonitrile, styrene, vinyl toluene, vinyl acetate, and alkyl (meth)acrylates.
The cross-linked cure in most latex formulations involves formaldehyde release, usually from reaction of methylolated acrylamide, although added aminoplast crosslinkers are also a common source. Because of recent health and environmental concerns associated with formaldehyde, there is a strong desire in the textile industry to reduce emissions and exposure to formaldehyde in the workplace. Formaldehyde is known to be a skin and eye irritant. Recent studies indicate that formaldehyde is mutagenic, and perhaps carcinogenic. Accordingly, latex formulations which eliminate components which evolve formaldehyde, or which reduce such evolution, are most desirable.
U.S. Pat. Nos. 4,076,870; 4,198,462; and 4,295,846 disclose processes for treating textile fibers using glyoxal curatives for low-formaldehyde release. The '870 patent, which is incorporated by reference, discloses the use of a fluorocarboxylic acid catalyst with imidazolidinone derivatives for fabric treatment. The '462 patent, which is incorporated by reference, teaches the use of urea/formaldehyde/glyoxal for treatment of fabrics. The '846 patent, which is incorporated by reference, discloses formaldehyde-free finishing agents for textiles containing urea/glyoxal.
It is the object of the present invention to provide a latex coating composition which substantially reduces the evolution of formaldehyde, while at the same time exhibiting good dry cleaning resistance and low temperature flexibility when used as a fabric coating.